Re: [Boost-users] [preprocessor] Enumerating sequence andshiftersequence

From: Paul Mensonides (pmenso57_at_[hidden])
Date: 2006-08-28 17:36:58

> -----Original Message-----
> From: boost-users-bounces_at_[hidden] 
> [mailto:boost-users-bounces_at_[hidden]] On Behalf Of 
> Paul Mensonides

> > I have the following sequence
> > 
> > #define SEQ (a)(b)(c)(d)
> > 
> > I want to transform it to something like this
> > 
> > F(a,b) F(b,c) F(c,d)
> > 
> > How can I do it efficiently and elegantly?
> > 
> > Thank you in advance.
> 
> Is F a macro?

In the mean time, the following should get you started...

#include <boost/preprocessor/cat.hpp>
#include <boost/preprocessor/control/iif.hpp>
#include <boost/preprocessor/tuple/eat.hpp>

#define A(seq) B(BOOST_PP_CAT(X0 seq, 0))
#define B(sf) C(BOOST_PP_CAT(Y1 sf, 0))
#define C(sf) Z0 sf

#define X0(x) (x) X1
#define X1(x) (1)(x) X2
#define X2(x) (1)(x) X1
#define X10 (0)
#define X20 (0)

#define Y1(x) (x, Y2
#define Y2(y) y) Y1
#define Y10
#define Y20

#define Z0(x, bit) (x Z1
#define Z1(x, bit) , x) BOOST_PP_IIF(bit, ZX, BOOST_PP_TUPLE_EAT(2))(x, Z2)
#define Z2(x, bit) , x) BOOST_PP_IIF(bit, ZX, BOOST_PP_TUPLE_EAT(2))(x, Z1)

#define ZX(x, next) (x next

#define SEQ \
    (a)(b)(c)(d)(e)(f)(g)(h)(i)(j)(k)(l)(m) \
    (n)(o)(p)(q)(r)(s)(t)(u)(v)(w)(x)(y)(z) \
    /**/

A(SEQ)

Regards,
Paul Mensonides